L does not equal the lifetime of just any old civilization, rather:

L = the amount of time a given planet will be transmitting intelligible symbolic language signals in the radio or other spectrums.

This is a highly debateable number. From our own experience we can set a lower bound of 100 years, but what is the upper bound? If our civilzation returns to a (radio) dark age due to a collaspe caused by overpopulation and/or climate change then our experience will tell us that 100 years is an unfortunate, but realistic estimate leading to a very pessimistic number for N.

However, what if we are heading towards an “omega point” as some have predicted, where we are overtaken by the intelligence of our machines and a supercivilization unhindered by mere biological lifespans and evolutionary patterns emerges (e.g. Carl Sagan’s “billion year old supercivilizations). Then who knows where the upper bound is or for that matter will it matter to us human beings in the end?

Then again, it is true that we have radio technology, but is that really a sign of intelligence on the cosmic scale. Pre-homo sapiens hominid species made and used tools, but did not have the intelligence our creative abilities to establish a culture that went from the sharpened rock scrapers to the bow and arrow and from hunter gathering to agriculture and an industrial revolution. To survive beyond the 5000 or so years of written languge civilization we must invent sustainable ways of using technology. We have not and may not ever do this, based on current experience.

To support the late Carl Sagan’s highly optimistic conclusions we need a value of L based on a radio technology civilization that concurrently has a sustainable means of supporting itself. We have no experience base for that. Therefore at this time N, in my opinion, has an indeterminate value.

Still, best of luck to all SETI researchers.

This show dealt with the recent Texas UFO case, of course, which I grant may rank as one of the sturdier cases, if only because the government is now admitting that they scrambled fighter jets after first denying it. Still, we should remember that UFO history is littered with the wreckage of cases that seemed quite sturdy at first. Roswell comes to mind, and of course that one really was a government cover-up, just not of UFOs. The Texas case is very recent, and it often takes time for these things to be sorted out. Bear in mind, at one time people were freaking out over George Adamski.

Shermer pointed out on the King show that there are residual cases in all fields of inquiry that are not quickly resolved. With something as fleeting as a UFO case, we may never know what those lights in the sky were.

I always thought it was interesting that UFOs tend to be seen more by one culture than another. It really is a white thing, more or less, isn’t it? The overwhelming percentage of the UFO witnesses, abductees, etc., tend to be caucasian. And the crop circles, mentioned earlier, seem to have a cultural center of gravity, too. They are heavily British, aren’t they?

Here is what I have been reading and accept to be the best and most plausible explanations to date.
http://en.wikipedia.org/wiki/Crop_circles
http://www.circlemakers.org/
http://www.amtsgym-sdbg.dk/as/crop/ufofake.HTM

I don’t doubt the possibility of extra terrestrial life forms at all, I simply think that crop circles, alone, are insufficient as proof of their arrival and the supporters of the alien cause hypothesis have yet to provide a compelling reason that leads me to believe that crop circles are caused by anything but human or some other natural phenomena.

I wish you luck in your quest to prove your assertions, but your arguments, as presented, don’t even tempt me, a layperson, to be interested in what you have to say.

-peace

http://www.reasons.org/resources/apologetics/design_evidences/1998_design_evidence_update.shtml

Examples (First 3 of 66)

1 – galaxy size
if too large: infusion of gas and stars would disturb sun’s orbit and ignite too many galactic eruptions.
if too small: insufficient infusion of gas to sustain star formation for long enough time.

2 – galaxy type
if too elliptical: star formation would cease before sufficient heavy element build-up for life chemistry.
if too irregular: radiation exposure on occasion would be too severe and heavy elements for life chemistry would not be available.

3 – galaxy location
if too close to a rich galaxy cluster: galaxy would be gravitationally disrupted
if too close to very large galaxy(ies): galaxy would be gravitationally disrupted.

What we need to hope for is that our civilisation will last long enough to begin sending a simple signal at a sufficient power level to attract attention from ET wherever he may be. Hopefully it wont have to be a distress signal.

Maybe rape never evolved? Maybe they’re herbivorous? any number of differences from human animals would produce very different civilizations. To assume our civilization is standard seems very silly to me.

It may be well established (in your mind) that “humans are VERY capable of being 100% responsible for every crop circle ever discovered.”

But you would be wrong. You intensity of you confidence does not seem, I believe, correlate to the intensity of your own investigation.

Not only has never been demonstrated (incl the BBC thing in New Zealand) that humans ARE capable of doing this, but there are no serious, respected scientists who will endorse your claim.

Lastly, the suggestion that you might know the mind of an with the intelligence to get here, is well, arrogant…though very humanesque.

Since you suggested a comparison to human culture, perhaps you could point me to an artist of any age whose work/designs resemble the designs in the crop circles.

This is my field and I can assure you, know one in the art world that I know has ever seen anything close to the kind of beauty of the crop circle designs from a human artist.

Off the top of your head, do you know how many crop circles appeared just this year?

Firstly, and most importantly, it is well established that humans are VERY capable of being 100% responsible for every crop circle ever discovered.

Secondly, would YOU travel several thousand light years just to draw some geometric pictures in the fields of a few farms as your ONLY form of communication to the local inhabitants? I seriously doubt it.

Even with the endless possibilities of what an alien culture might produce for an introduction ritual, using agricultural vandalism as your only way of saying “Hello” seems unlikely.

As appealing and romantic as the thought of ‘crop circles being caused by aliens’ might be, when you compare human capabilities (both culturally & technologically) verses what the likely motivations of a race capable of visiting planet Earth would be – crop circles don’t appear to present much evidence for contact with aliens.